Improvement in peopellers



CHARLES M. HARA, O-F NEW YORK, N. Y

Letters .Patent No. 76,651, dated April 14, 1868.

IMPROVEMENT vIN PROPELLERS;

dlgs ttsttlr referat it it tinte trtisrsttent mit mating part rf tlnsame.

To ALL wHoM 1T MAY coNcEnN:

-Be it known that I, CHARLES M. OHARA, of. London, England, but now-residing in the city of New York, in the county and State of New York, have invented certain Improvements in a Propellexgfor which said propeller, Letters Patent of the United States were granted to me, bearingdate November 5, 1867, and numbered 70,460;v and I dol hereby declare'that the following is a full, clear, and exact description thercof,which will enable others skilled in the art to lmake and use the same, rference being had to the accompanying drawings,

vforming part of this specification.v l l In my present improvement I combine a horizontal engine with the propeller aforementioned. The engine is distinguished for a'peculiar shortness of stroke and ccmpactness of form, with its piston-rod or connectinggear attachedso near to the propellers axis that the distance therefrom does not exceed one-fourth part of the propellers radius.

The engine being adjusted in a horizontal position', and in a direct line with the vessels motion,'the power applied Ato the propeller is communicated to the vessel in the most eiiective manner possible. If, however', it be *Umore convenient, the engine can be adjusted so that its piston-rod, when taken with the line of the vessels motion,

will form au angle not exceeding forty-ve degrees. But I prefer the position irst mentioned, as the nearer the engine is placed in the line of the vessels movement, the more effective are the results obtained.V

When it is necessary that the engine should occupy a small space and be close to the propeller, it may be made to oscillate, and thereby correspond with the movement of the propeller, without the complication of guides and connecting-rods; The engine may also Vbe constructed with av trunk, after the manner of ordinary trunkengines, to eii'ect the same purpose. In the accompanyingdrawings- Figure 1 is a side view of my engine and propeller, applied at the stern of a vessel.

Figure 2 is a rear view, showing the impinging surface'of the propeller surrounded with a rim or flange, in combination with horizontal plates running parallel with'ach other; also an armor bell-crank at each extremity of the propellers axis, to which two connecting-rods are attached from a cross-head on the piston-rod of the engme.

Figure 3 is a side sectional view of the propeller, arranged with a weight or adjustable counterpoise. Figures 4 and 5 show propellers withtheir convex surfaces constructed of a round or angular form. Figure 6-shows the propeller with the piston-rod or connecting-shaft of the engine attached below the axis of the same. l

A represents the stern Aportion ef a vessel, having a trunk or chamber to receive the propeller, C. B represents-the engine, with its piston-rod, D, `connected to the propeller by means of an arm or bell-crank, E, and connecting-rod l?.4 This arm or bell-crank is rigidly attached to the propeller, either above or below the axis, and, when the propeller is atzhalf stroke, is in avertical position. The piston-rod D being attached to the proa eller in the manner before-shown and workin in the same manner as in an-'ordinar en ine actnates .the P 1, g y g i propeller in the manner. required, the extent'of the stroke being indicated by the red lines in the accompanying drawings. I

By adjusting' two Propellers on the same axis, one engine can be made to workboth of them, either at the stern or at the sides of a vessel. If theybe adjusted at. the side of the vessel, I purpose constructing the con? vex orcylindrical surface of each propeller round or angular, in order to oifer as little resistance as possible while passing` through the water in the direction of' the vessels movement.

' The other improvements referred to consist of constructing the propeller-with such a degree of lightness that its own buoyancy will render it in a manner self-acting, and cause it to return to its initial or startingpoint, without the aid 'of steam-power. This self-acting tendency maybe greatly increased by creating a vacuum in the steam-engine at the termination of each driving-stroke. In order, however, to prevent the propeller returningfto its initial or starting-point with too great a velocity, .it will be necessary to adjust a valve or stopcock to the ports or ducts of the engine, so as to moderate or shut oii the steam whenl required.

p For the purpose of balancing the propeller on its axis, and to regulate its action when Vthe vessel is carrying a light or heayy draught of water, a. weight or adjustable counterpoise (W, iig. 3,) is attached to the axis or any other part of theV propeller, in such e. manner that it can be adjusted in any position that maybe necessary. The impinging `surface of the propeller is surrounded with a flange or rim, in combination with a series of plates running in a. horizontal position, and parallel with each other, as shown in fig. 2 ofthe accompanying drawings, the object of which is to prevent a too rapid displacement of the water that opposes the prpellers action.

Having thus described my invention, what I claim as new, and desire to secure by Letters' Patent, is- The reversible buoyantppropeller, constructed and arranged to operate as herein described. t

' CHARLES M. OHARA..

Witnesses: i t

J. E. M. BOWEN, GEO. A. MORRISON. 

